The present invention relates to a library device for copying information from a copying source disk to each of a plurality of disks of library construction, and selecting each of the copied disks. The present invention also relates to a method for selecting copied disks by the library device.
A magneto-optical disk device is connected to a personal computer and so on, and has been used like a hard disk. The magneto-optical disk device has been used as all kinds of computer storage units from large-sized to small-sized due to its bulk, compatibility and high reliability.
In recent years, the magneto-optical disk device has been used for storing a plurality of magneto-optical disks of library construction. The magnet-optical disk device of library construction has been used as a server for a Local Area Network (LAN) system and also as a storage device for CAD (Computer Aided Design) / CAM (Computer Aided Manufacturing), since the magneto-optical disk device has a capacity ranging from a few Giga Bytes (GB) to scores of Giga Bytes per device.
Further, the magneto-optical disk device is very useful as a copying machine when the identical information is stored in each of the magnet-optic disks of library construction from a few sheets to about hundreds of sheets. Namely, the magneto-optical disk device has not been merely used as a storage unit, but also it has been used as a copying machine.
In the above-mentioned magneto-optical disk device of library construction, a storage unit stores a predetermined number of sheets of magneto-optical disks to be copied in corresponding storage racks. A disk moving unit takes out the magneto-optical disks from each of the storage racks, and inserts them into a drive unit.
Then, the personal computer copies informations from one sheet of a copying source magneto-optical disk, which was prepared previously to each of the magneto-optical disks that were inserted into the drive unit. Then, each of the copied magneto-optical disks is returned to the corresponding storage rack by the disk moving unit. In this case, there will not be any problems in particular if the information is copied correctly.
However, the device can not easily discriminate a disk in which a copying error has occurred, if the copying error (a copying process was completed abnormally) occurred when the information was copied into the large number of sheets of magneto-optical disks. Namely, there were not any methods for discriminating the magneto-optical disk in which the copying error has occurred, even though each of the magnet-optical disks into which the information are copied was stored in the corresponding storage rack.
For this reason, an error would occur if some processes were executed later by using the information stored in a magneto-optical disk having a copying error. As a result, the reliability of information processing is deteriorated.